Mofe Koya discusses the history of citizenship and naturalization in the United States. She first examines the constitutional framework behind the right to birthright citizenship, then explores how naturalization in the early twentieth century became a tool for defining and excluding who could belong in America, a pattern that may be reemerging as the impending review of Barbara v. Trump approaches the Supreme Court. Finally, she argues that the Court must reaffirm citizenship as a fixed constitutional guarantee rather than a political construct subject to shifting social or governmental priorities.